docs: def redo(self):
          """Redo the next metadata change.
  
          Returns
          -------
  
          up : UpdateInfo instance
          """
          args = self._undo_stack.forward()
          if args is None:
              return
          clusters, field, value, up, undo_state = args
          self.set(field, clusters, value, add_to_stack=False)
  
          # Return the UpdateInfo instance of the redo action.
          up.history = 'redo'
  
          self.emit('cluster', up)
          return up